Tools of the aforementioned kind have been found objectionable because of the excessive noise generated by detonation of the explosive charge. In some instances that noise is close to the threshold of pain. Attempts to meet that problem have not been successful for various reasons. A major difficulty arises from the conflicting requirements of noise suppression and the need for clearance space at the combustion zone to avoid deleterious build-up or residue. With regard to the last point, it is important to avoid build-up of combustion by-products (residue) between the working surfaces of the tool which might have the result of causing the tool to jam, as that can be hazardous to the user. If the clearance between working surfaces is increased to minimize the danger of jamming, it naturally follows that noise suppression will also be minimized. That is, the relatively large clearance allows a large volume of combustion gas at high pressure to issue from the tool at the one instant so that an intensely loud noise is generated.